What is the purpose of septoplasty, is it failed if my septum is still crooked?

This is challenging to answer without a thorough examination.
Nasal obstruction can be multifactorial - septal deviation, turbinate hypertrophy, nasal valve collapse (static or dynamic), and can change with allergies/weather/more.

Make sure you see a surgeon who is well-trained to evaluate these issues for you to get an accurate diagnosis as that's essential for a successful plan to improve the way you feel.

There are bones in the septum itself that may require resection or repair, but breaking (osteotomies) the nasal bones themselves is very uncommon to achieve a straight septum.